WEBVTT 00:00:00.000 --> 00:00:02.000 So, I want to start out with 00:00:02.000 --> 00:00:04.000 this beautiful picture from my childhood. 00:00:04.000 --> 00:00:06.000 I love the science fiction movies. 00:00:06.000 --> 00:00:08.000 Here it is: "This Island Earth." 00:00:08.000 --> 00:00:10.000 And leave it to Hollywood to get it just right. 00:00:10.000 --> 00:00:12.000 Two-and-a-half years in the making. 00:00:12.000 --> 00:00:15.000 (Laughter) 00:00:15.000 --> 00:00:18.000 I mean, even the creationists give us 6,000, 00:00:18.000 --> 00:00:20.000 but Hollywood goes to the chase. 00:00:20.000 --> 00:00:24.000 And in this movie, we see what we think is out there: 00:00:24.000 --> 00:00:27.000 flying saucers and aliens. 00:00:27.000 --> 00:00:30.000 Every world has an alien, and every alien world has a flying saucer, 00:00:30.000 --> 00:00:34.000 and they move about with great speed. Aliens. NOTE Paragraph 00:00:35.000 --> 00:00:38.000 Well, Don Brownlee, my friend, and I finally got to the point 00:00:38.000 --> 00:00:41.000 where we got tired of turning on the TV 00:00:41.000 --> 00:00:44.000 and seeing the spaceships and seeing the aliens every night, 00:00:44.000 --> 00:00:47.000 and tried to write a counter-argument to it, 00:00:47.000 --> 00:00:51.000 and put out what does it really take for an Earth to be habitable, 00:00:51.000 --> 00:00:53.000 for a planet to be an Earth, to have a place 00:00:53.000 --> 00:00:56.000 where you could probably get not just life, but complexity, 00:00:56.000 --> 00:00:58.000 which requires a huge amount of evolution, 00:00:58.000 --> 00:01:01.000 and therefore constancy of conditions. 00:01:01.000 --> 00:01:04.000 So, in 2000 we wrote "Rare Earth." In 2003, we then asked, 00:01:04.000 --> 00:01:09.000 let's not think about where Earths are in space, but how long has Earth been Earth? 00:01:09.000 --> 00:01:11.000 If you go back two billion years, 00:01:11.000 --> 00:01:13.000 you're not on an Earth-like planet any more. 00:01:13.000 --> 00:01:17.000 What we call an Earth-like planet is actually a very short interval of time. NOTE Paragraph 00:01:17.000 --> 00:01:19.000 Well, "Rare Earth" actually 00:01:19.000 --> 00:01:22.000 taught me an awful lot about meeting the public. 00:01:22.000 --> 00:01:25.000 Right after, I got an invitation to go to a science fiction convention, 00:01:25.000 --> 00:01:28.000 and with all great earnestness walked in. 00:01:28.000 --> 00:01:30.000 David Brin was going to debate me on this, 00:01:30.000 --> 00:01:34.000 and as I walked in, the crowd of a hundred started booing lustily. 00:01:34.000 --> 00:01:37.000 I had a girl who came up who said, "My dad says you're the devil." 00:01:37.000 --> 00:01:41.000 You cannot take people's aliens away from them 00:01:41.000 --> 00:01:45.000 and expect to be anybody's friends. 00:01:45.000 --> 00:01:47.000 Well, the second part of that, soon after -- 00:01:47.000 --> 00:01:50.000 and I was talking to Paul Allen; I saw him in the audience, 00:01:50.000 --> 00:01:52.000 and I handed him a copy of "Rare Earth." 00:01:52.000 --> 00:01:56.000 And Jill Tarter was there, and she turned to me, 00:01:56.000 --> 00:01:59.000 and she looked at me just like that girl in "The Exorcist." 00:01:59.000 --> 00:02:01.000 It was, "It burns! It burns!" 00:02:01.000 --> 00:02:03.000 Because SETI doesn't want to hear this. 00:02:03.000 --> 00:02:06.000 SETI wants there to be stuff out there. 00:02:06.000 --> 00:02:09.000 I really applaud the SETI efforts, but we have not heard anything yet. 00:02:09.000 --> 00:02:11.000 And I really do think we have to start thinking 00:02:11.000 --> 00:02:14.000 about what's a good planet and what isn't. NOTE Paragraph 00:02:14.000 --> 00:02:17.000 Now, I throw this slide up because it indicates to me that, 00:02:17.000 --> 00:02:21.000 even if SETI does hear something, can we figure out what they said? 00:02:21.000 --> 00:02:23.000 Because this was a slide that was passed 00:02:23.000 --> 00:02:27.000 between the two major intelligences on Earth -- a Mac to a PC -- 00:02:27.000 --> 00:02:30.000 and it can't even get the letters right -- 00:02:30.000 --> 00:02:32.000 (Laughter) 00:02:32.000 --> 00:02:34.000 -- so how are we going to talk to the aliens? 00:02:34.000 --> 00:02:37.000 And if they're 50 light years away, and we call them up, 00:02:37.000 --> 00:02:39.000 and you blah, blah, blah, blah, blah, 00:02:39.000 --> 00:02:42.000 and then 50 years later it comes back and they say, Please repeat? 00:02:42.000 --> 00:02:44.000 I mean, there we are. NOTE Paragraph 00:02:44.000 --> 00:02:47.000 Our planet is a good planet because it can keep water. 00:02:47.000 --> 00:02:51.000 Mars is a bad planet, but it's still good enough for us to go there 00:02:51.000 --> 00:02:53.000 and to live on its surface if we're protected. 00:02:53.000 --> 00:02:56.000 But Venus is a very bad -- the worst -- planet. 00:02:56.000 --> 00:02:59.000 Even though it's Earth-like, and even though early in its history 00:02:59.000 --> 00:03:02.000 it may very well have harbored Earth-like life, 00:03:02.000 --> 00:03:05.000 it soon succumbed to runaway greenhouse -- 00:03:05.000 --> 00:03:07.000 that's an 800 degrees [Fahrenheit] surface -- 00:03:07.000 --> 00:03:10.000 because of rampant carbon dioxide. NOTE Paragraph 00:03:10.000 --> 00:03:13.000 Well, we know from astrobiology that we can really now predict 00:03:13.000 --> 00:03:16.000 what's going to happen to our particular planet. 00:03:16.000 --> 00:03:19.000 We are right now in the beautiful Oreo 00:03:19.000 --> 00:03:22.000 of existence -- of at least life on Planet Earth -- 00:03:22.000 --> 00:03:25.000 following the first horrible microbial age. 00:03:25.000 --> 00:03:28.000 In the Cambrian explosion, life emerged from the swamps, 00:03:28.000 --> 00:03:30.000 complexity arose, 00:03:30.000 --> 00:03:33.000 and from what we can tell, we're halfway through. 00:03:33.000 --> 00:03:36.000 We have as much time for animals to exist on this planet 00:03:36.000 --> 00:03:38.000 as they have been here now, 00:03:38.000 --> 00:03:40.000 till we hit the second microbial age. 00:03:40.000 --> 00:03:42.000 And that will happen, paradoxically -- 00:03:42.000 --> 00:03:44.000 everything you hear about global warming -- 00:03:44.000 --> 00:03:47.000 when we hit CO2 down to 10 parts per million, 00:03:47.000 --> 00:03:49.000 we are no longer going to have to have plants 00:03:49.000 --> 00:03:53.000 that are allowed to have any photosynthesis, and there go animals. 00:03:53.000 --> 00:03:55.000 So, after that we probably have seven billion years. 00:03:55.000 --> 00:03:58.000 The Sun increases in its intensity, in its brightness, 00:03:58.000 --> 00:04:03.000 and finally, at about 12 billion years after it first started, 00:04:03.000 --> 00:04:06.000 the Earth is consumed by a large Sun, 00:04:06.000 --> 00:04:09.000 and this is what's left. 00:04:09.000 --> 00:04:13.000 So, a planet like us is going to have an age and an old age, 00:04:13.000 --> 00:04:17.000 and we are in its golden summer age right now. NOTE Paragraph 00:04:17.000 --> 00:04:19.000 But there's two fates to everything, isn't there? 00:04:19.000 --> 00:04:22.000 Now, a lot of you are going to die of old age, 00:04:22.000 --> 00:04:25.000 but some of you, horribly enough, are going to die in an accident. 00:04:25.000 --> 00:04:27.000 And that's the fate of a planet, too. 00:04:27.000 --> 00:04:31.000 Earth, if we're lucky enough -- if it doesn't get hit by a Hale-Bopp, 00:04:31.000 --> 00:04:35.000 or gets blasted by some supernova nearby 00:04:35.000 --> 00:04:38.000 in the next seven billion years -- we'll find under your feet. 00:04:38.000 --> 00:04:40.000 But what about accidental death? 00:04:40.000 --> 00:04:42.000 Well, paleontologists for the last 200 years 00:04:42.000 --> 00:04:44.000 have been charting death. It's strange -- 00:04:44.000 --> 00:04:47.000 extinction as a concept wasn't even thought about 00:04:47.000 --> 00:04:50.000 until Baron Cuvier in France found this first mastodon. 00:04:50.000 --> 00:04:52.000 He couldn't match it up to any bones on the planet, 00:04:52.000 --> 00:04:54.000 and he said, Aha! It's extinct. 00:04:54.000 --> 00:04:57.000 And very soon after, the fossil record started yielding 00:04:57.000 --> 00:05:00.000 a very good idea of how many plants and animals there have been 00:05:00.000 --> 00:05:02.000 since complex life really began to leave 00:05:02.000 --> 00:05:05.000 a very interesting fossil record. 00:05:05.000 --> 00:05:08.000 In that complex record of fossils, 00:05:08.000 --> 00:05:10.000 there were times when lots of stuff 00:05:10.000 --> 00:05:12.000 seemed to be dying out very quickly, 00:05:12.000 --> 00:05:14.000 and the father/mother geologists 00:05:14.000 --> 00:05:16.000 called these "mass extinctions." NOTE Paragraph 00:05:16.000 --> 00:05:18.000 All along it was thought to be either an act of God 00:05:18.000 --> 00:05:20.000 or perhaps long, slow climate change, 00:05:20.000 --> 00:05:22.000 and that really changed in 1980, 00:05:22.000 --> 00:05:25.000 in this rocky outcrop near Gubbio, 00:05:25.000 --> 00:05:28.000 where Walter Alvarez, trying to figure out 00:05:28.000 --> 00:05:31.000 what was the time difference between these white rocks, 00:05:31.000 --> 00:05:33.000 which held creatures of the Cretaceous period, 00:05:33.000 --> 00:05:35.000 and the pink rocks above, which held Tertiary fossils. 00:05:35.000 --> 00:05:39.000 How long did it take to go from one system to the next? 00:05:39.000 --> 00:05:41.000 And what they found was something unexpected. 00:05:41.000 --> 00:05:44.000 They found in this gap, in between, a very thin clay layer, 00:05:44.000 --> 00:05:47.000 and that clay layer -- this very thin red layer here -- 00:05:47.000 --> 00:05:49.000 is filled with iridium. 00:05:49.000 --> 00:05:52.000 And not just iridium; it's filled with glassy spherules, 00:05:52.000 --> 00:05:54.000 and it's filled with quartz grains 00:05:54.000 --> 00:05:58.000 that have been subjected to enormous pressure: shock quartz. NOTE Paragraph 00:05:58.000 --> 00:06:00.000 Now, in this slide the white is chalk, 00:06:00.000 --> 00:06:03.000 and this chalk was deposited in a warm ocean. 00:06:03.000 --> 00:06:05.000 The chalk itself's composed by plankton 00:06:05.000 --> 00:06:09.000 which has fallen down from the sea surface onto the sea floor, 00:06:09.000 --> 00:06:12.000 so that 90 percent of the sediment here is skeleton of living stuff, 00:06:12.000 --> 00:06:14.000 and then you have that millimeter-thick red layer, 00:06:14.000 --> 00:06:16.000 and then you have black rock. 00:06:16.000 --> 00:06:19.000 And the black rock is the sediment on the sea bottom 00:06:19.000 --> 00:06:21.000 in the absence of plankton. 00:06:21.000 --> 00:06:25.000 And that's what happens in an asteroid catastrophe, 00:06:25.000 --> 00:06:28.000 because that's what this was, of course. This is the famous K-T. 00:06:28.000 --> 00:06:30.000 A 10-kilometer body hit the planet. 00:06:30.000 --> 00:06:34.000 The effects of it spread this very thin impact layer all over the planet, 00:06:34.000 --> 00:06:37.000 and we had very quickly the death of the dinosaurs, 00:06:37.000 --> 00:06:39.000 the death of these beautiful ammonites, 00:06:39.000 --> 00:06:41.000 Leconteiceras here, and Celaeceras over here, 00:06:41.000 --> 00:06:43.000 and so much else. NOTE Paragraph 00:06:43.000 --> 00:06:45.000 I mean, it must be true, 00:06:45.000 --> 00:06:48.000 because we've had two Hollywood blockbusters since that time, 00:06:48.000 --> 00:06:51.000 and this paradigm, from 1980 to about 2000, 00:06:51.000 --> 00:06:56.000 totally changed how we geologists thought about catastrophes. 00:06:56.000 --> 00:06:59.000 Prior to that, uniformitarianism was the dominant paradigm: 00:06:59.000 --> 00:07:02.000 the fact that if anything happens on the planet in the past, 00:07:02.000 --> 00:07:06.000 there are present-day processes that will explain it. 00:07:06.000 --> 00:07:09.000 But we haven't witnessed a big asteroid impact, 00:07:09.000 --> 00:07:11.000 so this is a type of neo-catastrophism, 00:07:11.000 --> 00:07:14.000 and it took about 20 years for the scientific establishment 00:07:14.000 --> 00:07:16.000 to finally come to grips: yes, we were hit; 00:07:16.000 --> 00:07:20.000 and yes, the effects of that hit caused a major mass extinction. NOTE Paragraph 00:07:21.000 --> 00:07:23.000 Well, there are five major mass extinctions 00:07:23.000 --> 00:07:26.000 over the last 500 million years, called the Big Five. 00:07:26.000 --> 00:07:29.000 They range from 450 million years ago 00:07:29.000 --> 00:07:31.000 to the last, the K-T, number four, 00:07:31.000 --> 00:07:35.000 but the biggest of all was the P, or the Permian extinction, 00:07:35.000 --> 00:07:37.000 sometimes called the mother of all mass extinctions. 00:07:37.000 --> 00:07:40.000 And every one of these has been subsequently blamed 00:07:40.000 --> 00:07:42.000 on large-body impact. 00:07:42.000 --> 00:07:44.000 But is this true? NOTE Paragraph 00:07:45.000 --> 00:07:48.000 The most recent, the Permian, was thought to have been an impact 00:07:48.000 --> 00:07:50.000 because of this beautiful structure on the right. 00:07:50.000 --> 00:07:53.000 This is a Buckminsterfullerene, a carbon-60. 00:07:53.000 --> 00:07:56.000 Because it looks like those terrible geodesic domes 00:07:56.000 --> 00:07:58.000 of my late beloved '60s, 00:07:58.000 --> 00:08:00.000 they're called "buckyballs." 00:08:00.000 --> 00:08:02.000 This evidence was used to suggest 00:08:02.000 --> 00:08:06.000 that at the end of the Permian, 250 million years ago, a comet hit us. 00:08:06.000 --> 00:08:09.000 And when the comet hits, the pressure produces the buckyballs, 00:08:09.000 --> 00:08:11.000 and it captures bits of the comet. 00:08:11.000 --> 00:08:15.000 Helium-3: very rare on the surface of the Earth, very common in space. NOTE Paragraph 00:08:16.000 --> 00:08:18.000 But is this true? 00:08:18.000 --> 00:08:22.000 In 1990, working on the K-T extinction for 10 years, 00:08:22.000 --> 00:08:25.000 I moved to South Africa to begin work twice a year 00:08:25.000 --> 00:08:27.000 in the great Karoo desert. 00:08:27.000 --> 00:08:30.000 I was so lucky to watch the change of that South Africa 00:08:30.000 --> 00:08:33.000 into the new South Africa as I went year by year. 00:08:33.000 --> 00:08:35.000 And I worked on this Permian extinction, 00:08:35.000 --> 00:08:38.000 camping by this Boer graveyard for months at a time. 00:08:38.000 --> 00:08:41.000 And the fossils are extraordinary. 00:08:41.000 --> 00:08:43.000 You know, you're gazing upon your very distant ancestors. 00:08:43.000 --> 00:08:45.000 These are mammal-like reptiles. 00:08:45.000 --> 00:08:48.000 They are culturally invisible. We do not make movies about these. 00:08:48.000 --> 00:08:50.000 This is a Gorgonopsian, or a Gorgon. 00:08:50.000 --> 00:08:54.000 That's an 18-inch long skull of an animal 00:08:54.000 --> 00:08:58.000 that was probably seven or eight feet, sprawled like a lizard, 00:08:58.000 --> 00:09:00.000 probably had a head like a lion. 00:09:00.000 --> 00:09:02.000 This is the top carnivore, the T-Rex of its time. 00:09:02.000 --> 00:09:04.000 But there's lots of stuff. 00:09:04.000 --> 00:09:06.000 This is my poor son, Patrick. 00:09:06.000 --> 00:09:07.000 (Laughter) 00:09:07.000 --> 00:09:10.000 This is called paleontological child abuse. 00:09:10.000 --> 00:09:12.000 Hold still, you're the scale. 00:09:12.000 --> 00:09:17.000 (Laughter) NOTE Paragraph 00:09:18.000 --> 00:09:21.000 There was big stuff back then. 00:09:21.000 --> 00:09:24.000 Fifty-five species of mammal-like reptiles. 00:09:24.000 --> 00:09:27.000 The age of mammals had well and truly started 00:09:27.000 --> 00:09:29.000 250 million years ago ... 00:09:29.000 --> 00:09:32.000 ... and then a catastrophe happened. 00:09:32.000 --> 00:09:34.000 And what happens next is the age of dinosaurs. 00:09:34.000 --> 00:09:38.000 It was all a mistake; it should have never happened. But it did. 00:09:38.000 --> 00:09:40.000 Now, luckily, 00:09:40.000 --> 00:09:43.000 this Thrinaxodon, the size of a robin egg here: 00:09:43.000 --> 00:09:46.000 this is a skull I've discovered just before taking this picture -- 00:09:46.000 --> 00:09:48.000 there's a pen for scale; it's really tiny -- 00:09:48.000 --> 00:09:52.000 this is in the Lower Triassic, after the mass extinction has finished. 00:09:52.000 --> 00:09:55.000 You can see the eye socket and you can see the little teeth in the front. 00:09:55.000 --> 00:10:00.000 If that does not survive, I'm not the thing giving this talk. 00:10:00.000 --> 00:10:04.000 Something else is, because if that doesn't survive, we are not here; 00:10:04.000 --> 00:10:08.000 there are no mammals. It's that close; one species ekes through. NOTE Paragraph 00:10:08.000 --> 00:10:11.000 Well, can we say anything about the pattern of who survives and who doesn't? 00:10:11.000 --> 00:10:13.000 Here's sort of the end of that 10 years of work. 00:10:13.000 --> 00:10:16.000 The ranges of stuff -- the red line is the mass extinction. 00:10:16.000 --> 00:10:18.000 But we've got survivors and things that get through, 00:10:18.000 --> 00:10:22.000 and it turns out the things that get through preferentially are cold bloods. 00:10:22.000 --> 00:10:26.000 Warm-blooded animals take a huge hit at this time. 00:10:27.000 --> 00:10:29.000 The survivors that do get through 00:10:29.000 --> 00:10:32.000 produce this world of crocodile-like creatures. 00:10:32.000 --> 00:10:36.000 There's no dinosaurs yet; just this slow, saurian, scaly, nasty, 00:10:36.000 --> 00:10:41.000 swampy place with a couple of tiny mammals hiding in the fringes. 00:10:41.000 --> 00:10:44.000 And there they would hide for 160 million years, 00:10:44.000 --> 00:10:47.000 until liberated by that K-T asteroid. NOTE Paragraph 00:10:47.000 --> 00:10:49.000 So, if not impact, what? 00:10:49.000 --> 00:10:53.000 And the what, I think, is that we returned, over and over again, 00:10:53.000 --> 00:10:56.000 to the Pre-Cambrian world, that first microbial age, 00:10:56.000 --> 00:10:58.000 and the microbes are still out there. 00:10:58.000 --> 00:11:00.000 They hate we animals. 00:11:00.000 --> 00:11:02.000 They really want their world back. 00:11:02.000 --> 00:11:06.000 And they've tried over and over and over again. 00:11:06.000 --> 00:11:09.000 This suggests to me that life causing these mass extinctions 00:11:09.000 --> 00:11:12.000 because it did is inherently anti-Gaian. 00:11:12.000 --> 00:11:17.000 This whole Gaia idea, that life makes the world better for itself -- 00:11:17.000 --> 00:11:21.000 anybody been on a freeway on a Friday afternoon in Los Angeles 00:11:21.000 --> 00:11:23.000 believing in the Gaia theory? No. NOTE Paragraph 00:11:23.000 --> 00:11:26.000 So, I really suspect there's an alternative, 00:11:26.000 --> 00:11:28.000 and that life does actually try to do itself in -- 00:11:28.000 --> 00:11:30.000 not consciously, but just because it does. 00:11:30.000 --> 00:11:34.000 And here's the weapon, it seems, that it did so over the last 500 million years. 00:11:34.000 --> 00:11:37.000 There are microbes which, through their metabolism, 00:11:37.000 --> 00:11:39.000 produce hydrogen sulfide, 00:11:39.000 --> 00:11:42.000 and they do so in large amounts. 00:11:42.000 --> 00:11:45.000 Hydrogen sulfide is very fatal to we humans. 00:11:45.000 --> 00:11:49.000 As small as 200 parts per million will kill you. 00:11:51.000 --> 00:11:55.000 You only have to go to the Black Sea and a few other places -- some lakes -- 00:11:55.000 --> 00:11:59.000 and get down, and you'll find that the water itself turns purple. 00:11:59.000 --> 00:12:02.000 It turns purple from the presence of numerous microbes 00:12:02.000 --> 00:12:05.000 which have to have sunlight and have to have hydrogen sulfide, 00:12:05.000 --> 00:12:09.000 and we can detect their presence today -- we can see them -- 00:12:09.000 --> 00:12:11.000 but we can also detect their presence in the past. NOTE Paragraph 00:12:11.000 --> 00:12:13.000 And the last three years have seen 00:12:13.000 --> 00:12:16.000 an enormous breakthrough in a brand-new field. 00:12:16.000 --> 00:12:18.000 I am almost extinct -- 00:12:18.000 --> 00:12:20.000 I'm a paleontologist who collects fossils. 00:12:20.000 --> 00:12:23.000 But the new wave of paleontologists -- my graduate students -- 00:12:23.000 --> 00:12:25.000 collect biomarkers. 00:12:25.000 --> 00:12:29.000 They take the sediment itself, they extract the oil from it, 00:12:29.000 --> 00:12:31.000 and from that they can produce compounds 00:12:31.000 --> 00:12:35.000 which turn out to be very specific to particular microbial groups. 00:12:35.000 --> 00:12:39.000 It's because lipids are so tough, they can get preserved in sediment 00:12:39.000 --> 00:12:42.000 and last the hundreds of millions of years necessary, 00:12:42.000 --> 00:12:44.000 and be extracted and tell us who was there. NOTE Paragraph 00:12:44.000 --> 00:12:47.000 And we know who was there. At the end of the Permian, 00:12:47.000 --> 00:12:49.000 at many of these mass extinction boundaries, 00:12:49.000 --> 00:12:53.000 this is what we find: isorenieratene. It's very specific. 00:12:53.000 --> 00:12:57.000 It can only occur if the surface of the ocean has no oxygen, 00:12:57.000 --> 00:13:00.000 and is totally saturated with hydrogen sulfide -- 00:13:00.000 --> 00:13:03.000 enough, for instance, to come out of solution. 00:13:03.000 --> 00:13:07.000 This led Lee Kump, and others from Penn State and my group, 00:13:07.000 --> 00:13:10.000 to propose what I call the Kump Hypothesis: 00:13:10.000 --> 00:13:13.000 many of the mass extinctions were caused by lowering oxygen, 00:13:13.000 --> 00:13:17.000 by high CO2. And the worst effect of global warming, it turns out: 00:13:17.000 --> 00:13:20.000 hydrogen sulfide being produced out of the oceans. NOTE Paragraph 00:13:20.000 --> 00:13:22.000 Well, what's the source of this? 00:13:22.000 --> 00:13:26.000 In this particular case, the source over and over has been flood basalts. 00:13:26.000 --> 00:13:29.000 This is a view of the Earth now, if we extract a lot of it. 00:13:29.000 --> 00:13:31.000 And each of these looks like a hydrogen bomb; 00:13:31.000 --> 00:13:33.000 actually, the effects are even worse. 00:13:33.000 --> 00:13:36.000 This is when deep-Earth material comes to the surface, 00:13:36.000 --> 00:13:38.000 spreads out over the surface of the planet. 00:13:38.000 --> 00:13:41.000 Well, it's not the lava that kills anything, 00:13:41.000 --> 00:13:43.000 it's the carbon dioxide that comes out with it. 00:13:43.000 --> 00:13:46.000 This isn't Volvos; this is volcanoes. 00:13:46.000 --> 00:13:48.000 But carbon dioxide is carbon dioxide. NOTE Paragraph 00:13:49.000 --> 00:13:52.000 So, these are new data Rob Berner and I -- from Yale -- put together, 00:13:52.000 --> 00:13:54.000 and what we try to do now is 00:13:54.000 --> 00:13:57.000 track the amount of carbon dioxide in the entire rock record -- 00:13:57.000 --> 00:14:00.000 and we can do this from a variety of means -- 00:14:00.000 --> 00:14:02.000 and put all the red lines here, 00:14:02.000 --> 00:14:05.000 when these -- what I call greenhouse mass extinctions -- took place. 00:14:05.000 --> 00:14:07.000 And there's two things that are really evident here to me, 00:14:07.000 --> 00:14:10.000 is that these extinctions take place when CO2 is going up. 00:14:10.000 --> 00:14:13.000 But the second thing that's not shown on here: 00:14:13.000 --> 00:14:16.000 the Earth has never had any ice on it 00:14:16.000 --> 00:14:20.000 when we've had 1,000 parts per million CO2. 00:14:20.000 --> 00:14:22.000 We are at 380 and climbing. 00:14:22.000 --> 00:14:25.000 We should be up to a thousand in three centuries at the most, 00:14:25.000 --> 00:14:29.000 but my friend David Battisti in Seattle says he thinks a 100 years. 00:14:29.000 --> 00:14:31.000 So, there goes the ice caps, 00:14:31.000 --> 00:14:35.000 and there comes 240 feet of sea level rise. 00:14:35.000 --> 00:14:37.000 I live in a view house now; 00:14:37.000 --> 00:14:39.000 I'm going to have waterfront. NOTE Paragraph 00:14:39.000 --> 00:14:43.000 All right, what's the consequence? The oceans probably turn purple. 00:14:43.000 --> 00:14:46.000 And we think this is the reason that complexity took so long 00:14:46.000 --> 00:14:48.000 to take place on planet Earth. 00:14:48.000 --> 00:14:51.000 We had these hydrogen sulfide oceans for a very great long period. 00:14:51.000 --> 00:14:55.000 They stop complex life from existing. 00:14:55.000 --> 00:15:00.000 We know hydrogen sulfide is erupting presently a few places on the planet. 00:15:00.000 --> 00:15:04.000 And I throw this slide in -- this is me, actually, two months ago -- 00:15:04.000 --> 00:15:08.000 and I throw this slide in because here is my favorite animal, chambered nautilus. 00:15:08.000 --> 00:15:12.000 It's been on this planet since the animals first started -- 500 million years. 00:15:12.000 --> 00:15:15.000 This is a tracking experiment, and any of you scuba divers, 00:15:15.000 --> 00:15:18.000 if you want to get involved in one of the coolest projects ever, 00:15:18.000 --> 00:15:20.000 this is off the Great Barrier Reef. 00:15:20.000 --> 00:15:21.000 And as we speak now, 00:15:21.000 --> 00:15:24.000 these nautilus are tracking out their behaviors to us. NOTE Paragraph 00:15:24.000 --> 00:15:28.000 But the thing about this is that every once in a while 00:15:28.000 --> 00:15:30.000 we divers can run into trouble, 00:15:30.000 --> 00:15:32.000 so I'm going to do a little thought experiment here. 00:15:32.000 --> 00:15:35.000 This is a Great White Shark that ate some of my traps. 00:15:35.000 --> 00:15:38.000 We pulled it up; up it comes. So, it's out there with me at night. 00:15:38.000 --> 00:15:41.000 So, I'm swimming along, and it takes off my leg. 00:15:41.000 --> 00:15:44.000 I'm 80 miles from shore, what's going to happen to me? 00:15:44.000 --> 00:15:46.000 Well now, I die. 00:15:46.000 --> 00:15:48.000 Five years from now, this is what I hope happens to me: 00:15:48.000 --> 00:15:51.000 I'm taken back to the boat, I'm given a gas mask: 00:15:51.000 --> 00:15:54.000 80 parts per million hydrogen sulfide. 00:15:54.000 --> 00:15:58.000 I'm then thrown in an ice pond, I'm cooled 15 degrees lower 00:15:58.000 --> 00:16:02.000 and I could be taken to a critical care hospital. 00:16:02.000 --> 00:16:04.000 And the reason I could do that is because we mammals 00:16:04.000 --> 00:16:07.000 have gone through a series of these hydrogen sulfide events, 00:16:07.000 --> 00:16:09.000 and our bodies have adapted. 00:16:09.000 --> 00:16:13.000 And we can now use this as what I think will be a major medical breakthrough. NOTE Paragraph 00:16:13.000 --> 00:16:15.000 This is Mark Roth. He was funded by DARPA. 00:16:15.000 --> 00:16:19.000 Tried to figure out how to save Americans after battlefield injuries. 00:16:19.000 --> 00:16:21.000 He bleeds out pigs. 00:16:21.000 --> 00:16:24.000 He puts in 80 parts per million hydrogen sulfide -- 00:16:24.000 --> 00:16:27.000 the same stuff that survived these past mass extinctions -- 00:16:27.000 --> 00:16:29.000 and he turns a mammal into a reptile. 00:16:29.000 --> 00:16:33.000 "I believe we are seeing in this response the result of mammals and reptiles 00:16:33.000 --> 00:16:36.000 having undergone a series of exposures to H2S." 00:16:36.000 --> 00:16:38.000 I got this email from him two years ago; 00:16:38.000 --> 00:16:41.000 he said, "I think I've got an answer to some of your questions." 00:16:41.000 --> 00:16:43.000 So, he now has taken mice down 00:16:43.000 --> 00:16:47.000 for as many as four hours, sometimes six hours, 00:16:47.000 --> 00:16:49.000 and these are brand-new data he sent me on the way over here. 00:16:49.000 --> 00:16:54.000 On the top, now, that is a temperature record of a mouse who has gone through -- 00:16:54.000 --> 00:16:56.000 the dotted line, the temperatures. 00:16:56.000 --> 00:16:58.000 So, the temperature starts at 25 centigrade, 00:16:58.000 --> 00:16:59.000 and down it goes, down it goes. 00:16:59.000 --> 00:17:01.000 Six hours later, up goes the temperature. 00:17:01.000 --> 00:17:06.000 Now, the same mouse is given 80 parts per million hydrogen sulfide 00:17:06.000 --> 00:17:08.000 in this solid graph, 00:17:08.000 --> 00:17:10.000 and look what happens to its temperature. 00:17:10.000 --> 00:17:12.000 Its temperature drops. 00:17:12.000 --> 00:17:16.000 It goes down to 15 degrees centigrade from 35, 00:17:16.000 --> 00:17:19.000 and comes out of this perfectly fine. NOTE Paragraph 00:17:19.000 --> 00:17:22.000 Here is a way we can get people to critical care. 00:17:22.000 --> 00:17:27.000 Here's how we can bring people cold enough to last till we get critical care. 00:17:28.000 --> 00:17:32.000 Now, you're all thinking, yeah, what about the brain tissue? 00:17:32.000 --> 00:17:35.000 And so this is one of the great challenges that is going to happen. 00:17:35.000 --> 00:17:37.000 You're in an accident. You've got two choices: 00:17:37.000 --> 00:17:40.000 you're going to die, or you're going to take the hydrogen sulfide 00:17:40.000 --> 00:17:43.000 and, say, 75 percent of you is saved, mentally. 00:17:43.000 --> 00:17:45.000 What are you going to do? 00:17:45.000 --> 00:17:48.000 Do we all have to have a little button saying, Let me die? 00:17:48.000 --> 00:17:50.000 This is coming towards us, 00:17:50.000 --> 00:17:52.000 and I think this is going to be a revolution. 00:17:52.000 --> 00:17:55.000 We're going to save lives, but there's going to be a cost to it. NOTE Paragraph 00:17:55.000 --> 00:17:57.000 The new view of mass extinctions is, yes, we were hit, 00:17:57.000 --> 00:17:59.000 and, yes, we have to think about the long term, 00:17:59.000 --> 00:18:01.000 because we will get hit again. 00:18:01.000 --> 00:18:03.000 But there's a far worse danger confronting us. 00:18:03.000 --> 00:18:06.000 We can easily go back to the hydrogen sulfide world. 00:18:06.000 --> 00:18:08.000 Give us a few millennia -- 00:18:08.000 --> 00:18:10.000 and we humans should last those few millennia -- 00:18:10.000 --> 00:18:14.000 will it happen again? If we continue, it'll happen again. 00:18:14.000 --> 00:18:16.000 How many of us flew here? 00:18:16.000 --> 00:18:18.000 How many of us have gone through 00:18:18.000 --> 00:18:21.000 our entire Kyoto quota 00:18:21.000 --> 00:18:23.000 just for flying this year? 00:18:23.000 --> 00:18:26.000 How many of you have exceeded it? Yeah, I've certainly exceeded it. 00:18:26.000 --> 00:18:29.000 We have a huge problem facing us as a species. 00:18:29.000 --> 00:18:31.000 We have to beat this. 00:18:31.000 --> 00:18:35.000 I want to be able to go back to this reef. Thank you. NOTE Paragraph 00:18:35.000 --> 00:18:41.000 (Applause) NOTE Paragraph 00:18:41.000 --> 00:18:43.000 Chris Anderson: I've just got one question for you, Peter. 00:18:43.000 --> 00:18:45.000 Am I understanding you right, that what you're saying here 00:18:45.000 --> 00:18:47.000 is that we have in our own bodies 00:18:47.000 --> 00:18:51.000 a biochemical response to hydrogen sulfide 00:18:51.000 --> 00:18:54.000 that in your mind proves that there have been past mass extinctions 00:18:54.000 --> 00:18:56.000 due to climate change? NOTE Paragraph 00:18:56.000 --> 00:18:58.000 Peter Ward: Yeah, every single cell in us 00:18:58.000 --> 00:19:01.000 can produce minute quantities of hydrogen sulfide in great crises. 00:19:02.000 --> 00:19:03.000 This is what Roth has found out. 00:19:03.000 --> 00:19:05.000 So, what we're looking at now: does it leave a signal? 00:19:05.000 --> 00:19:07.000 Does it leave a signal in bone or in plant? 00:19:07.000 --> 00:19:10.000 And we go back to the fossil record and we could try to detect 00:19:10.000 --> 00:19:12.000 how many of these have happened in the past. NOTE Paragraph 00:19:12.000 --> 00:19:14.000 CA: It's simultaneously 00:19:14.000 --> 00:19:17.000 an incredible medical technique, but also a terrifying ... NOTE Paragraph 00:19:17.000 --> 00:19:20.000 PW: Blessing and curse.